Broaching machine



w. A. HART 2,190,067

BROACHING MACHINE Feb. 13, 1940.

Filed Sept. 28, 1935 2 Sheets-Sheet 1 INVENTOR. lVz'ZZz'a /7, fiarit ATTORNEYS BROAGHING MACHINE Filed Sept 28, 1935 2 Sheets-Sheet 2 h zZZz'dW f7. f/ari ATTORNEYS.

INVENTOR.

Patented Feb. 13, 1940 uir PATENT OFFlCE BROACHIN G MACHINE MichiganApplication September 28, 1935, Serial No. 42,619

' 1 Claim. (01. 90-43) Thepresent invention relates to metal workingmachines, and more particularly to improved mechanism for automaticallymoving the cutting I and work supporting elements of such machines.

It isan object of the present invention to provide a metalworking'machine embodying improved means for effecting relativereciprocatory motion between a tool head and Work support- 10 ing table.

It is also an object of the present invention to provide a fluidpressure operated cylinder for use.

in metal working machines and the like,'and particularly adapted toimpart a reciprocatory 15 motion to a tool head.

It is also an object of the present invention to provide a cylinder ofthe lastmentioned type, embodying a stationary piston and a movablecasing therefor, for supporting a tool head, in

20 which the fluid pressure intake and exhaust lines may all beconnected to thepiston rod.

It is also an object of thepresent invention to provide a cylinder ofthe last mentioned type, in which the movable casing is free of fluidpres- 25 sure connections.

It is also an object'of the present invention to provide a fluidpressure operatedcylinder of the above mentioned type in which theintake and exhaust lines may both be connected at the same 30 end of thepiston structure.

It is also an object of the present invention to provide a fluidpressure operated cylinder embodying a two-passagepiston rod,constructed to accommodate fluid pressure intake and exhaust 35 linesand in which one of the passages communicate with the interiorof thepiston casing on one side of the piston, and the other passagecommunicates with the interior of thecasing on the other side of thepiston.

40 It, is also an object of the present invention to provide a fluidpressure operated cylinder embodying a movable casing and a stationarypiston, in which the piston is constructed to provide two concentricpassages, one of which com- 45. municates with one side of the pistonhead and the other of which communicates with the other side of thepiston head.

It is also an object of the present invention to provide a metal workingmachine embodying a 50 pivotally supported work table, and automaticmeans to pivot the table from a cutting position to a loading position.

It is a further object of the present. invention to provide a metalworking machine of the last s mentioned type in which the pivotalmovements or" the work table are controlled in accordance with themovements of the machine cutting tool.

It is a further object of the present invention to generally improve andsimplify metal Working machines, particularly those constructed to 0p- 5erate broaching tools, and to provide an automatic machine which issimple in construction, economical of manufacture, and accurate andpositive in operation.

Other objects of the present invention appear in the followingdescription and in the appended claim.

In the drawings, throughout which corresponding reference characters areused to designate corresponding parts:

Fig. 1 is a view in perspective of a broaching machine embodying a fluidpressure operated cylinder constructed in accordance with the presentinvention; l

Fig.2 is a view in vertical section of a fluid pressure operatedcylinder embodying the, present invention;

Fig. 3is a view in vertical section of illustrative fluid pressureconnections to the piston. rod of the cylinder shown in Fig. 2;

Fig. 41s a View in horizontal section taken along the line 4-4 of Fig.1;. and

Fig.5 is a view inside elevation of a broaching machine embodying apivoted work table in accordance with the present invention.

As will be understood, metal working machines, such for example asautomaticbroachin-g machines, compromise in general a. table forsupporting the work to be machinedor broached, a corresponding supportfor a cutting tool, and means to impart relativemotion to the work pieceand the cutting tool. In certain instances, the work piece isstationarily supported during a cutting movement and the cutting tool isreciprocated withrespect thereto. Alternatively, the cutting tool may bestationarily supported and the work piece reciprocated with respectthereto.

In the practice of both of these alternative arrangements, it has becomecustomary to uti- 45 lize fluid pressure operated mechanism to providethe relative motion between the work piece and the outtingtool, and animportant feature of the presentinvention is the provision of animproved construction of fluid pressure operated cylinder for effecting'suchautornatic relative movement.

In the form illustrated, Y the improved fluid pressure operated cylinderof the present invention, comprises generally a casing within which 5 apiston is slidably supported and to which a piston rod is connected.Preferably, and as illus trated, the piston rod is stationarilysupported and in operation, the casing reciprocates with respect to thepiston head, the cutting tool being supported on the exterior of thecasing.

To effect movement of the casing in one direction, fluid is introducedinto the casing on one side of the piston and is exhausted from thecasing on the other side of the piston. To produce an opposite directionof casing movement, a reverse transfer of fluid is effected.

In the form illustrated, the piston rod consists of two concentricallyformed conduits, corresponding ends of which are fixed in the pistonhead and to a stationary support respectively. The inner conduitregisters with a central opening cut through the piston head, and thuscommunicates with the interior of the casing on one side of the pistonhead. The outer conduit is provided with peripheral openings adjacentthe point at which it is connected to the piston head, and thuscommunicates with the interior of the casing on the opposite side of thepiston head. The piston rod conduits may be selectively dimensioned toproduce any desired relation between the rates of travel of the casingin the respective directions.

The intake and exhaust lines may be connected to the piston rod invarious ways. Preferably, and as illustrated, the intake and exhaustlines lead to the stationary piston rod support, and are connected tothe piston rod conduits through cross passages formed in such support.

As will be understood, the feature of connecting the intake and exhaustlines to the stationary portions of the cylinder eliminates thenecessity of flexible supply lines, and thus materially simplifies theconstruction. It also avoids the neces sity of connecting fluid linesinto the casing. Since the connections to the casing portions on the twosides of the pistons are arranged within the single piston rod, such rodneed extendonly on one side of the piston head, and provision isrequired for passing such piston rod through only one end of the casing.With this arrangement, accordingly, packing mechanism is required atonly one point in the unit.

In the use of the improved cylinder of the present invention,particularly in connection with automatic broaching machines, thecomplete travel cycle of the cylinder casing is preferably automatic;that is, after having been started in motion, it travels to one limit oftravel, is automatically reversed, travels to an opposite limit oftravel and is again automatically reversed. The automatic reversingmechanism may be arranged in various ways. A preferred arrangement foraccomplishing this is disclosed in the co-pending application of RichardA. Thompson, Serial No. 35,693, filed August '7, 1935, and assigned tothe same assignee as the present application. As disclosed in thatapplication, suitable reversing valve mechanism is provided, andarranged for movement from a position corresponding to one direction offlow, to a position corresponding to an opposite direction of fiow,asthecasing approaches opposite limits of travel. A reversing movement of thevalve reverses the connection of the cylinder supply line to a source ofpressure and an exhaust line.

To facilitate the insertion and removal or work, and ensure that thecutting tool shall not engage the work during a return movement of theformer, it has been found desirable to provide means to withdraw thework during such return movement,

and a further feature of the present invention is the provision of animproved, pivotally supported work table, in combination with automaticmeans to swing the table between loading and cutting positions inaccordance with the movements of the cutting tool. The illustratedarrangement is such that at the completion of a cutting movement, thework table is automatically swung to a loading position, at which itremains throughout the return movement of the cutting tool. At thecompletion of the return movement, and the beginning of a new cuttingmovement, the work table is automatically swung to a cutting position,in which it remains throughout the cutting movement. Preferably, and asillustrated, the actuating mechanism for the work table comprises afluid. pressure cylinder, the connections to which are reversed at theabove mentioned limits of travel by a suitable reversing control valvewhich responds to the position of the cutting tool.

Referring to Figs. 1 through 4 of the drawings, an illustrative machinewith which the improved cylinder of the present invention may be used,comprises generally the supporting frame Ill, the vertical forward faceof which is recessed to accommodate the cylinder mechanism designatedgenerally l2, and the lower forward portion I4 of which is horizontallydisposed to provide a suitable table upon which the work to be broachedor machined (not shown) may be positioned. A preferred form of worktable is disclosed in Fig. 5 and is described below. The cylindermechanism I2 is provided with the laterally extending rail sections [6,which are slidably supported against the face of the frame H] by theguides I8. Guides 18 are secured to frame If] by studs 20. The forwardface of the cylinder mechanism I2 is adapted to form a support for toolcarriage 22, which is secured thereto by the countersunk studs 24.Cutting tool 26 is fitted in a longitudinal recess formed in carriage 22and is secured therein by the countersunk studs 30.

As best shown in Figs. 2 and 4, cylinder mechanism l2 comprises theouter hollow cylindrical sleeve 32, within which the hollow casing 34 isrelatively tightly fitted. The lower ends of sleeve 32 and casing 34 areclosed by the plate 36, which is secured to casing 32 by studs 38. Theupper ends of sleeve 32 and easing 3d are closed by collar 49, retainingrings 42 and 44, and by the piston rod designated generally 46. Collar40 is secured to sleeve 32 by studs 48. Retaining ring 44, which isprovided with a central aperture dimensioned to slidably receive pistonrod 46, is press fitted within collar 40 and is supported against theannular shoulder 50 formed near the lower end thereof. Retaining ring42, provided with a correspondingly dimensioned central aperture toreceive piston rod 46, is press fitted into the upper end of collar 40and is supported against the annular shoulder 52 formed in ,the latter.A suitable packing gland 54 is interposed between rings 42 and 44 toprevent the escape of fluid to the exterior of the cylinder.

Piston 46 comprises the two concentric hollow conduits 56 and 58. Thelower end of conduit 56 is externally threaded, and is threaded into theupper end of piston head 69. Theupper end of conduit 56, as best shownin Fig. 3, is threaded into the stationary support 62, which may form apart of the machine frame 10. The upper and lower ends of the innersleeve 58 are correspondingly externally threaded, and are threaded intosupport 62 and piston head 60,

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aieoper respectively. As will be understood, piston head 60 is slidablysupported within casing --34, and

may, if desired; be provided with a plurality municate with the fluidsupply lines 10 and 12, through the cross passages 14 and "I6 formed insupport62. I

The boss T8 formed on the lower end of plate 36 is of substantially thesame diameter as the inner conduit 58 and is in axial alignmenttherewith. At the upper limit of the stroke of oasing 34, boss 18 entersthe lower end of conduit 58 and forms a fluid cushion for casing 34. Acorresponding cushion is provided at the lower limit of travel of casing34 by sleeve 80 which surrounds the outer conduit 56, and is disposed toenter a cooperating area 82 provided by th formation of the lower end ofcollar 46.

With reference to the operation of the cylinder mechanism as a whole, itwill be understood that fluid introduced under pressure through intakeline I0, circulates through the space between conduits 56 and 58,through the openings 66, and into the upper portion of casing 34. Thisaction develops a pressure tending to force casing 34 upwardly. Inresponse to this movement, the fluid which normally occupies the lowerportion of casing 34 is forced therefrom through conduit 58 and outthrough the line 72. To effect I a downward movement of cylindermechanism I2, fluid is introduced through line 12, and circulatesthrough conduit 58 into the lower portion of casing 34, forcing thelatter downwardly. In response to this movement, the fluid previouslyintroduced into the upper portion of casing 34 is forced outwardlythrough opening 66, through the space between conduits .56 and 56 andout through line I0. It will beunderstood ber respectively, is disclosedin the above identified co-pending application of the present applicant.

Referring now to Fig. 5, work piece I06 and a usual rest I08 thereforare removably secured to the upper surface IIO of work table H2 by theillustrative clamping mechanism II4. Clamping mechanism II4 maybe of anysuitable type and as illustrated comprises the clamp II6, pivotallysecured by pin H8 to a support I20 which may be formed integrallywithwork table H2. The eccentric I22 may be rotated by arm I24 to forceclamp II'6 tightly into engagement with work piece I06.

Work table I I2 is pivotally supported on shaft I26 to the mainsupporting frame I0, and is adapted to be automatically swung betweenthe full line and dotted line positions by the fluid {pressuremechainism designated "generally 428. In the run line position,' theupper flat surrace I-t0 of table Hrbfears against the shoulder I-30formed-in frameJ-D; The tool 26, in passing across the workpiece 166,tends to rotatetable II 2 in a counterclockwise direction, as viewed inFig. 5, the shaft I26 being-prefeiablylocated in offset relation to thepathiofmo'vementof tool -26. The force thus applied by the topicspositively maintains table 2in the cutting-posi- I tion. In the fullline position, a willbe understood, table I I2 holds workpiece HJG incutting position with respectto cutting tool 26. Inthe dotted line orloading position of table I", work piece 106 is swung out of the path ofcutting tool-26, and is not engaged thereby during its return movement.The movement of table I I! to the loading position, in addition toavoiding engagement between the cutting tool and the work piece duringthe return movement of the former, also facilitates the removal of thecompleted work piece I06 and the insertion of a new work piece.

The fluid pressure mechanism I28 may be constructed in various ways. Asillustrated, it comprises a piston I32, slidably received within thecasing I34, and pivotally connected to work table Il2 through the pistonrod I36. Casing I34 is pivotally supported to frame I04 by shaft I38,and is provided with the side openings I40 and I42, into which the endsof the flexible supply lines I44 and I46 respectively are secured.

The other ends of supply lines I44 and I46 are connected to a suitableconventional reversing valve I48, the actuating arm I50 of which issubject to control by a lower cam I52,.which moves with tool 26, as Wellas by an upper cam I54, which also moves with tool 26, and is disposedto engage a rocker arm I56. Rocker arm I56 is connected to arm I50through push rod I58.

It will be understood that in one position, valve I48 connects line I46to a source of fluid pressure illustrated as pump I60, and connects lineI44 to a suitable exhaust chamber (not shown) through line I62; and thatin a reverse position it connects line I44 to pump I60 and connects lineI46 to the exhaust chamber.

With reference to the operation of the unit as a whole, the parts areshown in the positions occupied when in readiness for a cutting movement of tool 26. In thesepositions, cam I54 retains the valve actuatingarm I50 in the illustrated position, in which line I44 is connected topump I60. These connections forcibly retain piston I42 in the upperillustrated position within cylinder I34, and force work table II2 tothe full line or cutting position.

This positioning of the part obtains until the completion of a cuttingmovement of tool 26, at which time cam I52 engages valve arm I50,

rotating it in a clockwise direction to a-position in which the valveconnections are reversed. With the reversed connections, line I46 isconnected to pump I60 and piston I32 is accordingly forced to anopposite position in cylinder I34 and in the course of this movementrotates work table I I2 around shaft I26 to the loading position shownin dotted lines, in which work piece I06 is out of the path of cuttingtool 26. This positioning of the parts obtains until, at the completionof a return movement, cam I54 again engages arm I56 and moves valve armI50 to the illustrated position. At this time work table I I2 is againswung in a counter-clockwise direction to the cutting position.

Although specific embodiments ofthe present invention have beendescribed, it will be vident that various modifications may be made inthe low piston rods extending through the other end of said cylinder andconnected to said piston for, supporting the same, the inner of saidhollow rods defining the fluid inlet and outlet pas.- sage for one endof the cylinder and the space between the rods defining the fluid inletand outlet passage for the other end of the cylinder, a stationarypiston rod supporting head secured to the frame adjacent one end of theways and having a pair of separate fluid passages formed therein, theinner rod being fixedly connected to and supported by said head in fluidcommunication with one of said head passages, and the outer rod beingfixedly connected to and supported by said head with the space betweensaid rods in fluid communication with the other head passage, and meanson said cylinder intermediate its ends for supporting a broaching tool.

WILLIAM A. HART.

